Looks like easy way is install clean partition this new os and copy all files form 1.4.5 expect them what allready exits in 3.7 installation (such copying is easy using directory opus) ? i hope its so easy. if so i do it soon and get mos3.7 (or later if we get new version before i have money buy it) next year if all goes well many things what are not related me. Only few partition related things are bit hard i must move m current one system by hand luckily i have backup these inoriginal hd where i copied stuff in new hd. When is very safe operation. Even more becouse i changed hd only needing bigger not reason old hd dont work well.
and very likely i dont need much 1.4.5 after 3.7. I dont know any reason expect testing if code something works old or not. and if there is bugs what kind bugs they are... i want support also 1.4.5 if there is any reason support only later systems.
Totally offtopic: to me i dont have custom mui setting for differnet programs. to me such a thing sounds silly. to me GUI should be similar in all programs makes using harder is not true...' to me custom guis removes one important points of GUI. like some programs have different order thier for example ok and cancel buttons than os standrdard way (which if i remember correctly is different in Mac OS X than Windows) this comment is not related MOS but GUI...
ps. very likely i going code and use few amiga speffic programs what i like.