The car is definitely worth it. The saying goes that these "bricks" can break 500k with a little love, and I for one believe it.
My 1993 245 has about 200k and runs like it was manufactured last week, and it easily breaks 30MPG.
Only 1 previous owner is a very good sign. The minor mechanical issues which you claim to be able to deal with yourself should be of no concern.
Regarding the cold load, its pretty much the same information you will find in the instructions booklet.
Regarding the engine being interference or not I can't say thanks to my poor terminology. This is what I could find on wiki:
1985–1995 B230 — 2.3 litres - 2,316 cubic centimetres (141.3 cu in) SOHC 8-valve Volvo 240/740/Volvo 940
1988–1993 B230F — 9.8:1 compression — 114 horsepower (85 kW; 116 PS) — U.S. models