a std switching relay is fine, ce1 digi mk2 uses a vw 53 relay for the ecu which will be fine. what i do is go to scrappy and chop out a load of relay holders for my looms, that way they clip neatly to the top of the fusebox. can be a mare to unclip just look at em carefully you'll see there is either 1 clip in the middle or 2 clips either side of the relay holder. dont get too rough or you'll snap the clips off and defeat the whole point of using the holder

CE1 plug D is for the engine loom, these are the pins you want to be looking at:
D
2 - blk - ignition live feed (this is the one digifant uses to trigger the ecu relay)
7 - blk - ignition live feed (also a blk/yel to the coolant level relay, dont cut that one splice to the black wire)
13- red/yel-fuel pump relay earth trigger
23- blk - ignition coil live feed
26- red/blk- rev counter feed, may need a conversion box depending how you trigger your spark
in addition:
E/14 - red/wht - should be a spade on this one, this is a fuel pump live. could use this for lambda and/or fuel injectors
N - fuel pump feed - the spade connector on this one is massive so would need to find one big enough. plus it unfused so bear that in mind