pdp11 bus - how long can it go?

As I slowly dig into "my" new 11/34A, I'm amazed by the bus configuration. Starting from the CPU, the main BA11 chassis has a double (9-slot) system unit, joined to a single (4-slot) SU by an?M9202 jumper. From the last slot in the chassis, a Unibus cable runs to a junction block on the cabinet back door. A second cable runs from there to a remote BA11, also with 2 SUs. A third cable runs back to the rack door/junction block (labled "bus station", BTW) and finally a fourth cable runs to a small rack mounted I/O box with a single SU and?an M9302 terminator in the last slot. Cable runs must be about 20-25 feet total. At first, I was worried that the length was too long (though it was a working system in use for several years) but after a quick websearch (www.psych.usyd.edu/pdp-11/unibus.html), I see that the bus can be up to FIFTY FEET before a repeater is needed. My short term plan is to pull all the cables and move the 9302 into the system box for testing. Now I'm worried that the bus might be too short - do I need to look for one of the "new" jumpers with two feet of cable or should it work with my old M9202 jumper block? Jack