You’ll forgive me if I write further about Bill, and somewhat personally rather than about our ThunderCats work. So if your only interest is ThunderCats – move on!
Bill and Gloria were huge in my life and remain gigantic in my memory.Both died too young and left an aching void. They lived in a sprawling old house on an ice pond: Ice Pond Farm. Gloria named every creature for miles around, including two recognizable fish in the huge pond: Jules and Sylvia Bass. They had a Doberman, Cooper, a superb physical specimen but severely brain-damaged and obsessed with fallen fruits which he would proudly lay at your feet. They were all over the house. A one-legged crow, Kriter, who accompanied them on walks, flying just above their heads. That all came to a halt when Kriter savagely attacked a friend’s bald head, causing real damage and drawing a lot of blood. From then on Kriter lived in a cage in the conservatory, creating an ungodly din as he hopped up and down on his one leg.
Bill had a superb studio which featured a huge old church lectern. While he drew (when he was working on the strips) Gloria read an endless series of novels standing at the lectern. If, that is, she wasn’t working at the Bronx Zoo. She was a shit-shoveller. Literally. An ex-dancer, tiny but tireless. She outworked the of the crew of criminals, semi-criminals and scary hard cases. Every year she and Bill held a party at Ice Pond Farm and every one of the crew showed up. To see the respect and affection they showed Gloria was profoundly touching.
Bill’s art was – is – quite remarkable. A giant talent. The level of detail and authenticity is astonishing. 
Even now, when I look at my copy of Rudy I see specifics I had not noticed before. And Rudy? A talking vaudeville chimp in Hollywood? Way ahead of its time – and, of course, a failure; at least in financial terms. His direction of the action within the frames of his strips was quite superb, a quality he shared with Len.
As to his novels, which include Moonlight Surveillance, Pieces of a Hero, Once More the Hero, Shanghai Tango, The Evil Chaser, The Divide, The Man from Raffles, and A Few Good Men, they are as original and spectacularly observed as you would expect. He wrote a number of screenplays for Rankin/Bass, including The Last Dinosaur, The Bermuda Depths, Ivory Ape and Bushido Blade. 
He had an odd relationship with Arthur Rankin, who produced those movies. Genuine affection but some bitterness revolving around the financial agreements. This latter doesn’t surprise me because RB was definitely on the tight side!
I have been stupid lucky to have worked with great talents over the years. It has always been – remains – shocking how so many of them struggle financially where others demonstrably less talented thrive. I believe that to succeed one needs three basic elements: talent, persistence and luck. 
It really doesn’t matter the balance between them but I do know this for certain sure: all the talent and persistence in the world will not get you there if you don’t have a measure of luck. Bill was beyond lucky in Gloria but, in my view, had very little professional luck.
Bill and Gloria were huge in my life and remain gigantic in my memory. Both died too young and left an aching void.